Electrical stop motion for knitting machines



April 25, 1949- A c. w. ARROwooD 2,468,611

ELECTRICAL STOP MOTION FOR KNITTING MACHINES I if@ 3 40 i l l 1 Aprl 26, 1949. c. w. ARRowoOD 2,468,611

ELECTRICAL STOP MOTION FOR KNITTING MACHINES 2 Sheets-Sheet 2 Filed May 13, 1947 Patented Apr'. Z6, 1949 UNITED STATES PATENT QFFICE ELECTRICAL STOP MOTION FOR KNITTING MACHINES Charles W. Arrowood, Charlotte, N. C.

Application May 13, 1947, Serial No. 747,7 06

9 Claims. 1

This invention relates to a stop motion for knitting machines and more especially to a very delicately arranged mechanism which is capable of being used with line denier nylon yarns, which heretofore have not operated satisfactorily with conventional stop motions. The present stop motion mechanism is so designed that it will laccurately control the machine and while the yarn is being used, it will hold the parts in the proper position and when the yarn is thrown out of operation by a change of feed, the vibra-tion of the machine will not gradually move the switch to closed position to stop the machine, but a sudden parting of Ithe yarn will allow centrifugal force of the operating mechanism to move the parts to a position where the machine will be instantly stopped. Great Adiillculty has been experienced in stop motions where, when a yarn is thrown out of oper-ation by fthe knitting machine, the increasing slackness in t-he yarn and vibration of the machine will fallow a sweep which is engaged by the yarn to gradually continue to move until a switch will be closed which will stop the machine when the machine should not be stopped.

It is an object of :this invention to provide a stop motion mechanism comprising a circuit which is normally held open by the normal tension of a yarn being knitted by the knitting machine and which switch will remain open when the yarn is thrown out of loperation and is not being used, due -to the fact that a sweep which is engaged by the arm will not move far enough due to slackening of the yarn on account of vibration, when not in use, to allow the switch to be closed. The mechanism employs a switch which is normally held in open position while the yarn is passing therethrough and which will remain open when the yarn is Ithrown out of operation, but which switch. will be closed upon excessive tension occurring in the yarn while it is being knitted or in the event of a parting of the strand of yarn which will allow the sweep engaged ,by the yarn to move further than it would move .under a slackening of the yarn and to .thereby close this switch to stop the machine upon a sudden parting of the yarn.

Some of `the objects of the invention having been stated, other objects will appear :as the description proceeds when taken in connection with the accompanying drawings, in which Figure 1 is a front elevation of the stop mo` Figure 2 is an end elevation looking to the left from the right-hand end of Figure l and showing portions broken away;

Figure 3 is anelevation of .the left-hand end of the apparatus as shown in Figure 1;

Figure 4 is a vertical sectional view taken along the line 'I-'I in Figure 1, but showing the parts I in the position as shown in Figure 5;

Figure 8 is a view similar to Figure 4, but showing the parts in the position they will occupy when the sweep is in the position shown in Figure 6;

Figure 9 is a view similar to Figure 4 but showing the par-ts in position when a yarn has Kbeen .thrown out of operation but the strand not parted. Referring more specically to the drawings,

the numeral I0 indicates a metallic electrically conductive housing which is adapted tc have a transparent covering II secured over its iront open side by any suitable means such as screws I2. The housing Il] has integral therewith an uprising block portion I3 which -is adapted to be secured to a bracket or arm I4 of a knitting machine by means of suitable screws I 5.

The housing I0 has oscillatably mounted therein a shaft It which extends from both of the two end walls of the housing and on Ione end has secured thereon by means of a set screw I'I an eccentric member I8. This eccentric member has screws 20 and 2| threadably mounted in opposed sides thereof which are adapted to engage the two arms of a sweep member 22 which is substantially U-shaped and projects outwardly and downwardly and has a horizontal portion 22a which normally occupies a substantially horizontal position during normal operation.

Secured on ythe back of the housing III, by any suitable means such as a screw 23', is :an arm 24 having a porcelain fitting 25 thereon providing a gap 23 in which a strand of yarn 29 is adapted to :have movement when the -parts are in the position shown in Figures 1, 2, 3 and 4.

The shaft at the end remote from the weight I8 has secured thereon a segment-a1 cam member by any sui-table means such as a set screw 3|. This cam member has two cam surfaces 33 and 34 which are adapted to engage one at a time a tension arm 35 oscillatably secured on a screw 35 threadably imbedded in the right-hand end wall of the housing Ill when viewed in Figure l.

The tension arm 35 has an inturned portion 31 tting against the back of the housing ID. The screw 36 has a serrated disk member 45 xedly secured on its outer end and the screw has loosely mounted thereon a sleeve 4I which is surrounded by a torsion spring 42 having one end 43 penetrating a suitable hole in disk 4D, and the other end of the spring is secured-in ahole 46-in the tension member 35.

Secured to the lower exterior surface of the housing IU by means of a screw 50 is a leaf spring 5I which has a projection 52 on its free end which is adapted to engage the serrations in the periphery of the wheel 4I). The amount of tension eX- erted by the spring 5i can be regulated by means of a suitable screw 53.

It is evident that the wheel 40 can be rotated in a counter clockwise direction, looking at the right-hand end of Figure l, which will increase the tension applied to the member 35 while clockwise motion of hand wheel 40 would decrease the tension.

Penetrating a suitable hole in the upper wall of the housing I is a screw 55 which has suitable insulating washers E and 5l on the upper and lower surfaces of the upper wall of the housing I D and also has therearound a suitable spacer washer 58 if desired. Thel screw 55 penetrates a leaf spring contact member 5D and the contact member 60 is held inposition by means of a suitable nut 6I separately secured on the lower end of screw 55. This arrangement insulates the screw 55 from the housing I0.

The screw 55 secures in position a suitable terminal clip 63 in which a conducting wire 64. is adapted to be secured, and this conducting wire 64 leads to a suitable stop motion mechanism and then through wire 58 to a suitable source of current 65 and from the other side of the source of current 55,- a wire 65 is connected to the bracket I4 or to the knitting machine of which it forms a part, and thus the housing Ill is grounded to thus complete a circuit when the switch in the housing is closed.

Secured on the shaft I6 by any suitable means suchas a set screw 'lil isa collarli which has projecting from-one side thereof a flattened double-ended cam portion 'l2 having an upper planar portion 'ltranda lower' planar portion Iwhile the planar portions .'13 and '14 are beveledas at 'I5 and 'IS respectively. The planar portion 13 is also beveled as atl?. Disposed belowthe portion 'I2 is a block 80 which is secured to the bottom of the housing by any suitable means such as a screw 8l. This block 8U has a cavity 82 extending upwardly from the bottom of the block 85 to near the top and the lower wall of the housing I0 fhas threadablymounted therein `a screw `83 which is locked in position by jamb nut 84 'and which projects into the cavity 82, and resting on the upper end of the screw 83 is a disk member 88. Resting on top of the disk 88is'acompression spring 85 whose upper end presses against an v enlarged portion 85 of a plunger 8l, the plunger 8'! being adapted to cooperate with the pori-ion 'l2 previously described. The enlarged portion 66 limits upward movement of the plunger 8l, this plunger 8l being in uppermost position in Figures 4 and 9.

4 Method of operation With the parts in the position shown in Figures l, 2, 3 and 4 the normal tension ci the yarn 29 passing above the horizontal portion 22a of the sweep will thus cause the cam surface 33 to be slightly engaging the tensioned member but not enough tension will be imparted to the sweep 22 to move the tensioned member 35 appreciably from the back wall of the housing I0. In this position, cam portion I2 will be occupying the position shown in Figure 4, and thus the cam portion will not be engaging the leaf spring contact member 60.

sweep and below the-porcelainguide 25.

It will also be noted that the eccentric weight member I8 will be moved to such a position that a large part of the weight will be balanced on the shaft I6 decreasing any additional tension on yarn while active, but there will still be enough weight tending to rotate the member I8 in a counter clockwise manner in Figure 3 to exert tension on the yarn, and the tension of the yarn will-hold'the member 'I2 out of contact with the leafspring contact member 6B during normal operation of the machine.

Now whenthe tension in the yarn increases by reasonof the yarn being hung on the cone for other reasons, the sweep 22 will be moved downwardly towards the position shown in Figure 6. This will cause the cam member 'l2 to occupy the position shown in Figure 8, and the beveled portion "Il will engage the leaf spring contact inember 6B and thus close the circuit to stop the machine since the circuit leads through a suitable and conventional stop motion mechanism on the machine whichis not shown or described. After thel cam portion Il has made Contact with the leaf spring contact 60 and the various parts occupy the position shown in Figures 6 and 7 the sweep 22 continues in itsrdownward path until the yarn is pulled free of the portion 22a. In this casethe peripheral portion of cam will slide on the tension arm thereby maintaining the same amount of tension on the yarn during the time required to stop the machine and without increasing the tension on the yarn until the yarn slidesA off the sweep portion22a. The cam portion l2 will occupy the position shown in Figure 8 whenlthis takes place. The wire 64 leads to a suitable stop motion mechanism and then from the stop motion mechanism may lead back by means of wire 59 to the source of current and to thegrounded framework of the machine. In this position the plunger 8l lwill serve as a stop to the downward movement of the sweep 22 since the ilat surface I4 engages the side edge of the plunger 8l and will not depress it.

Now let us assume that during normal operation of the'machine, one yarn is thrown out of operation and another yarn called into use and in which case there usually results a gradual slackening of the discontinued yarns. This will cause thesweep 22 to move upwardly with the yarn .29 disposed still above the two legs of the As the yarn gradually slackens the sweep may move upwardly to the position shown in Figure 9 where the cam surface 'I4 will engage the upper end of plunger :81, but the'inertia of eccentric portion I8 will not be suilicient to depress the plunger 8l, and therefore, the camsurface 'I3 or its sloping or beveled surface 15 will not engage the leaf spring contact 60, and thus the circuit will not becompletedand the machine will not be stopped on account of the slackening of the yarn because this movement would be gradual, and there would not be enough centrifugal force exerted by the eccentric member I8 to move the sweep 22 up to the position shown in Figure 5.

With the sweep lowered by excessive tension in the yarn to the position shown in Figure 6, it is seen that the cam surface 33 will move the tensioned member away from contact with the back surface of the housing I0 and the resistance to this movement will be gradually increased on account of building up resistance in the torsion spring 44. The cam member 34 will in this case occupy the position shown in Figure 7.

Now when the sweep 22 moves upwardly as a result of slackening of the tension in the yarn due to its non-use, the cam member likewise will rotate in a clockwise manner in Figure 2 to the position shown in Figure 9 the portion 15 will not engage contact 60.

Now in the event there is a sudden parting of the strand of yarn, the sweep 22 not being held in lowered position by the yarn, will suddenly swing upwardly and due to the centrifugal force of inertia in the eccentric member I8, the shaft I6 will be rotated to a greater amount than would be the case in a gradual slackening of the yarn, and the parts would. move to the position shown in Figure 5. This will cause one end of the cam portion 12 to depress the plunger 81 and the beveled portion 15 of the cam portion 1I) will engage and slightly raise the leaf spring contact member 60 to hold the parts in the position shown in Figure 5 and stop the machine also. When the parts assume the position shown in Figure 5 as a result of a sudden surface 34 of member 30 will occupy a position parallel to and in contact with the front edge of the tensioned member 35, but will not move it on its pivot for the reason that one of the projecting ends of the sweep 22 which is nearest the housing I!! will engage the back leg of the bracket 24 and stop counter clockwise rotation of the member I8 as viewed in Figure B.

In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specic terms are employed, they are used in a generic and descriptive sense only, and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. An electric stop motion for knitting machines comprising a housing having a guide arm extending therefrom in xed position, an oscillatable shaft mounted within the housing and having a weight member eccentrically mounted thereon, a sweep arm attached to said eccentrically mounted weight member and extending outwardly on each side of the fixed arm so that a strand passed below the fixed arm and the sweep member while under tension will hold the sweep member in a definite position relative to the fixed arm, said shaft extending outside the other end of the housing and having a cam member thereon and a tensioned arm adapted to engage the cam member, the housing being grounded to one side of an electrical circuit and a leaf spring contact member disposed within the housing and connected to another side of the electrical circuit, cam means mounted on said shaft and adapted to engage said, leaf spring Contact member when excessive tension occurs in the yarn and the said cam member being adapted to also engage the leaf spring member when the yarn suddenly parts and allows the eccentrically mounted weight member to rotate the shaft to its limits to thereby parting of the yarn, the

move the sweep upwardly far enough to allow the Acam member to engage'said leaf Contact member.

2. Electrical stop motion means for knitting machines comprising a housing and an oscillatable shaft mounted thereon, and a sweep arm mounted on the shaft and adapted to be held in one position by normal tension in the yarn, means on the shaft for closing a circuit when excessive tension is present in the yarn, means for preventing the means on the shaft from closing a circuit when tension gradually decreases in the yarn due to increasing slackness, and weight means on said shaft adapted to rotate said shaft upon slackness occurring gradually in the yarn, said Weight means also being adapted to rotate said shaft, upon a sudden parting of the yarn, a greater distance than can occur due to gradually increasing slackness in the yarn.

3. A switch structure for electric stop motions for knitting machines and the like comprising a casing, an oscillatable shaft mounted in the casing and extending from both ends thereof, a sweep member having two arms mounted on said shaft, a collar having a flattened double ended cam portion and being mounted on said shaft, tension means adapted to be engaged by one end of said flattened portion when the sweep member is swung to one position to retard movement of said shaft, an electrical terminal element within the casing and engageable by the other end of said flattened portion when the sweep member is moved a predetermined amount by excessive tension in the yarn, weight means mounted on one end of the shaft and adapted to move the shaft far enough upon a sudden parting of the yarn to cause the other first-named end of Said flattened portion to engage said terminal to close a circuit and a cam member mounted on one end of the shaft extending beyond the housing and tension means adapted to be engaged by the cam member when excessive tension is imparted to the yarn to gradually increase the resistance to movement of the shaft by the excessive tension on the yarn, until a predetermined tension is reached, and then maintaining a constant resistance to movement of the sweep member until the sweep member is moved far enough to allow the yarn to move off the free end of the sweep member.

4. In a switch structure comprisingr a casing and an oscillatable shaft mounted in the casing. and an eccentric member mounted on the shaft and having a sweep extending therefrom adapted to be held in lowered position by the tension of the yarn passing thereover, an electric contact mounted in close proximity to the shaft, a doubleended cam portion mounted on the shaft, one end of the cam portion adapted to engage said contact when excessive tension appears in the yarn, the other end of said lever being adapted to engage said contact when the yarn parts to allow the shaft to oscillate to its extreme limit, and resilient means adapted to engage one of the ends of the double-ended cam portion on said shaft to prevent oscillation of the shaft far enough to engage the electric contact upon a gradual slackening of the tension in the yarn.

5. In an electrical stop motion for knitting machines comprising a casing and an oscillatable shaft mounted in the casing and an eccentrically mounted weight member mounted on the shaft and a sweep arm extending from the weight member adapted to be held in a predetermined position by normal tension of the yarn, an electrical terminal mounted in the casing, a double-ended cam portion mounted on said shaft, movement of the sweep arm on account of excessive tension in the yarn being adapted to move the shaft sufliciently to cause one end of the double-ended cam portion to engage the electric terminal to closea circuit to stop the machine, spring means adapted to engage the other end of said cam portion when the shaft is allowed to oscillate on account of a gradual slackening of the yarn to prevent the other end of said cam portion from engaging the electric terminal, the weight member being adapted to oscillate said shaft sufficiently to overcome the tension means and allow one end of said cam portion to engage the terminal to close a circuit to stop the machine upon .a sudden parting ofthe yarn, said shaft also having a cam member mounted thereon and other tension means engageable by the cam member to gradually increase resistance to oscillation of the shaft due to an increased tension of the yarn beyond'normal tension.

6. In an electrical stop motion for knitting machines comprising an electrical terminal,r a member adapted to engage said electric terminal, means controlled by normal tension in the yarn for. preventing the member from engaging the electrical terminal, means for causing the member to engage the electrical terminal upon a sudden parting of the yarn, resilient means for preventing the member from engaging the terminal upon a gradual slackening of the yarn and other resilient means for offering increased resistance to movement of the member upon excessive tension appearing in the yarn.

7. In a switch structure comprising a. casing and an oscillatable shaft mounted in the casing, and an eccentric member mounted on the shaft and having a sweep extending therefrom adapted to be held in lowered position by the tension of the yarn passing thereover, an electric contact mounted in close proximity to the shaft, a doubleended. cam portion mounted on the shaft, one end of the cam portion adapted to engage said Contact when excessive tension appears in the yarn, the other end of said cam portion being adapted to engage said contact when the yarn parts to allow the shaft to oscillate to its extreme limit, and resilient means adapted to engage one of the ends of the double-ended cam portion on said shaft to prevent oscillation of the shaft far enough to engage the electric Contact upon a gradual slackening of the tension in the yarn, a segmental member mounted on the shaft, an adjustable spring-pressed member in close proximity to the segmental member and limited in its movement towards the segmental member and adapted to be engaged by one of the radially disposed sides of the segmental member, and by the arcuate periphery of the segmental member after the sweep has been lowered a predetermined amount by an increase in the tension of the yarn.

8. In an electrical stop motion for `knitting machines comprising a casing and an oscillatablev shaft mounted in the casing and an eccentrically mounted weight member mounted on the shaft and a sweep arm extending from the Weight member adapted to be held in a predetermined position by normal tension of the yarn, an electrical terminal mounted in the casing, a double-ended portion mounted on said shaft, movement of the sweep arm on account of excessive tension the yarn being adapted to move the shaft sufficiently to cause one end of the double-ended cam portion to engage the electric terminal to close a circuit to stop the machine, spring means adapted to engage the other end of said cam portion when the shaft is allowed to oscillate on account of a gradual slackening of the yarn to prevent the other end of said cam portion from engaging the electric terminal, the Weight member being adapt-ed to oscillate said shaft sufficiently to overcome the tension means and allow one arm of said cam portion to engage the terminal to close a circuit to stop the machine upon a sudden parting of the yarn, said shaft also having a cam member mounted thereon and other tension means engageable by the cam member to gradually increase resistance to oscillation of the shaft due to an increased tension of the yarn beyond normal tension, until the yarn tension has reached a predetermined pull, after which the last-named tension means exerts a constant resistance to oscillation of the shaft.

9. In an electrical stop motion for knitting machines comprising an electric terminal, a member adapted to engage said electric terminal, means controlled by normal tension in the yarn for preventing the member from engaging the electrical terminal, means for causing the member to engage the electric terminal upon a sudden parting of the yarn, resilient means for pref venting the member from engaging the terminal upon a gradual slackening of the yarn and other resilient means for offering increased resistance to movement cf the member upon excessive ten` sion appearing in the yarn, the resilient means for offering increased resistance to the movement of the member, exerting a constant resistance aftera predetermined amount of resistance has been reached.

CHARLES W. ARROWOOD.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,079,341 Wachsman May 4, 1937 2,121,375 Wachsman June 21, 1938 2,121,376 Wachsman et al. June 21, 1938 2,178,982 Wachsman Nov. 7, 1939 2,184,107 Wachsman Dec. 19, 1939 2,248,315 Wachsman July 8, 1941 2,420,513 Arrowood May 13, 1947 I y Certificate of^rCo1rectionl1 4 Patent No. 2,468,611. yApril 26, 1949; CHARLES W. ARROWOOD It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows Column 6, line 59, claim 4, for the Word lever read cam portion;

and that the said Letters Patentshould be` read With this correction therein that the same may conform to the record of the case in the P atent Office.

Signed and Sealed this 9th day of August, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uommz'ssoner of Patents.

I Certicate of- YCorrection Patent No. 2,468,611. y ,Apri1\26, 1949;

CHARLES W. ARROWOOD It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:r

Column 6, line 59, claim 4, for the word "1ever read cam portion;

and that the said Letters Patent-should be read With this correction therein that the same may conform to the record of the case in the Patent Ofce.

Signed and sealed this 9th day of August, A. D. 1949.

THOMAS F. MURPHY,

Assistant 'ommz'ssioner of Patents. 

